1. Field of the Invention
The present invention generally relates to a motor with a thrust bearing and, more particularly, to a motor capable of steady rotation.
2. Description of the Related Art
Referring to FIG. 1, a sketch diagram of a conventional motor with a thrust bearing is shown, which is identified with a reference number of “9” and which has a seat 91, a stator 92 and a rotor 93. The seat 91 is coupled with a bearing housing 911 receiving a thrust bearing 912 and a pushing board 913 inside. The bearing housing 911 has two opposite openings for the rotor 93 to extend into the thrust bearing 912 and to couple with a lid 914 respectively. The stator 92 is coupled with an outer periphery of the seat 91. The rotor 93 includes a hub 931 integrally forming an annular wall 932 and a shaft 933. The annular wall 932 is located between the seat 91 and the bearing housing 911, to provide functions such as dust-resistance and anti-leakage of oil. The shaft 933 extends through the thrust bearing 912 and couples with the pushing board 913. Specifically, this kind of motor 9 is disclosed in patents such as a China patent application with the application number of 200410054614.4 (which is US Pat. No. 7,021,829) and title of “Fluid-Dynamic-Pressure Bearing, Spindle Motor Furnished with the Fluid-Dynamic-Pressure Bearing, Method of Manufacturing Rotor Assembly Applied in the Spindle Motor, and Recording-Disk Drive Furnished with the Spindle Motor.”
With the above structure, in rotation of the rotor 93 relative to the thrust bearing 912, an upper surface of the pushing board 913 abuts against the thrust bearing 912 with a large area “F”since this upper surface contacts with a lower surface of the thrust bearing 912. As a result, in operation of the rotor 93, friction between the pushing board 913 and the thrust bearing 912 is large, which affects the rotation of the rotor 93 significantly. Therefore, it is necessary to improve the conventional motor 9.